US3409094A - Spring actuated core retainer - Google Patents

Description

Nov. 5, 1968 T. R. KRETSCHMER ETAL 3,409,094

SPRING ACTUATED CORE RETAINER 2 Sheets-Sheet 1 Filed May 31, 1967 IN HEODCRJARE R. K

VENTORS RETSCHMER ELVI N C. HIRONAKA JOSEPH H. GOLANT A r TOR/V5 Y 1968 T. R. KRETSCHMER ETAL 3,409,094

SPRING ACTUATED CORE RETAINER 2 Sheets-Sheet 2 Filed May 31, 1967 Fig.3

United States Patent 3,409,094 SPRING ACTUATED CORE RETAINER Theodore R. Kretschmer, Port Hueneme, and Melvin C.

Hironaka, Camarillo, Calif., assignors to the United States of America as represented by the Secretary of the Navy Filed May 31, 1967, Ser. No. 643,325 7 Claims. (Cl. 175-242) ABSTRACT OF THE DISCLOSURE The invention is a spring actuated core retainer comprising a tubular body which is to be attached to the lower end of a core sampling barrel. Within the body are two rotatable closure elements connected to two torsion springs which tend to bias the closure elements so as to close the core barrel after a sample has been taken. Holding means restrain the closure elements during descent and penetration of the core barrel; upon removal of the barrell, pressure from the ocean sediment pivots the holding means from engagement with the closure means allowing the torsion springs to bias the closure elements to a closed position.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

Background of the invention Field of the invention.This invention relates to a closure device and more particularly to a spring actuated core retainer to be used in combination with a core barrel for the purpose of retaining core samples taken from the ocean bottom.

Description of the prior art.The problem of retaining a core sample taken from the ocean bottom has long been known by oceanographers and has sparked various devices as solutions to the problem. One of the early devices consisted of flexible metal fingers mounted on a ring which fitted into the interior of a core barrel near the cutting shoe. These flexible metal fingers allowed the core sample to enter but were biased so that the sample was prevented from movement out of the barrel. The primary disadvantage of this type of device was that it restricted the core barrel entrance during corer penetration and it seriously disturbed and remodeled the core sample as the sample entered the core barrel.

Another device consisting of a pair of jaws mounted on a frame which slides up and down the exterior of the core barrel has been developed; this device is held externally on the core barrel by a hook at a longitudinal position approximately equal to the expected core barrel penetration. Ideally the jaws will be resting upon the surface when the core barrel has finished its penetration and as the core barrel is retrieved the jaws close over the end of the barrel when the barrel reaches the sediment surface. However, the disadvantages with this apparatus are that the depth of penetration of the core barrel cannot be predicted closely enough to allow proper positioning of the jaws, nor do the jaws completely and effectively prevent a core sample loss since immediately upon pulling a suction is exerted on the core sample tending to pull the sample out of the core barrel. The result is that in many cases the core sample has been lost by the time the core barrel has been completely removed from the sediment.

A third type of core retainer which is of recent design is best illustrated by a patent to J. E. Sanders et al., Patent No. 3,285,354, which illustrates a retainer consisting of two curved gates which are linked to a longitudinally 3,409,094 Patented Nov. 5, 1968 sliding external sleeve. The sleeve is in an upward position upon penetration of the core barrel, thus holding the gates open, and the sleeve is forced into a lower position upon removal of the barrel, thus causing the gates to close. Such a device is a definite improvement over the first two devices mentioned; however, it too has disadvantages in that it will only operate in certain types of ocean sediment such as firmly packed sand, but such a device would not work in looser types of sediment which would not be able to establish the required forces upon the sliding sleeve to cause closure. In addition, the requirements of a sliding sleeve and corresponding linkages leading to the gates necessitate an overly large di ameter core barrel which, in turn, establishes a poor area ratio (the area ratio is the ratio of the difference between the sectional core barrel area and the sectional core sample area to the sectional core sample area).

Summary of the invention Our invention solves the abovementioned problems by providing a device which will work in all types of underwater sediment and which has a very good area ratio. The advantages are achieved by providing a spring actuated core retainer comprising in combination a tubular body, a hinge connected to the tubular body, a closure means rotatably attached to the hinge for opening and closing the interior of the tubular body, spring means connected to the tubular body and to the closure means for biasing said closure means into a closed position, and a retention means connected to the tubular body and the closure means for selectively holding the retainer means in an open position, and responsive to downward sediment pressure for releasing the closure means, whereby the closure means in held open by the retention means during penetration of the device into the ocean bottom and the closure means is biased closed during pullup of the device from the ocean bottom.

An object of the invention is to provide a spring actuated core retainer which is operable in all types of ocean bottom sediments and especially in soft cohesive materials.

Another object of the invention is to provide a spring actuated core retainer which has a low area ratio thus causing the least disturbance to a soil sample.

Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings wherein:

Brief description of the drawings FIG. 1 is a partial sectional view of a preferred embodiment of our invention showing the device in an open position to receive a core sample;

FIG. 2 is a full sectional view taken along line 2-2 of FIG. 1;

FIG. 3 is a partial sectional view of the FIG. 1 embodiment illustrating the device in a closed position; and

FIG. 4 is a full sectional view taken along line 44 of FIG. 3.

Description of the preferred embodiment Referring now to the drawings wherein like reference numerals designate like or corresponding parts throughout the several views there is shown in FIG. 1 a sectional view of our apparatus in an open position. The apparatus comprises a tubular body 10 having an upper portion 12 and a lower portion 14 and having an exterior portion or surface 16 and interior portion 18. The tubular body may be connected at its upper portion 12 to a core barrel 20 by any suitable means such as a bayonet connection (not shown). The interior of the core barrel 20 may be a core sample liner 22 which may be used to protect and house a core sample so as to expedite handling and storage of a core sample once it is brought back to a surface vessel. A cutting shoe 24 may be connected to the lower portion 14 of the tubular body byany suitable means such as by being threaded thereon as designated at 26.

-T he tubular body may have oppositely disposed longitudinal grooves 28 and 30 out within its interior portion 18 and transversely oppositely disposed apertures 32 and 34 drilled through the body, the grooves and apertures for receiving the mechanisms necessary to achieve the advantages of our invention.

The remaining elements of our invention which are mostly housed in the interior 18 of the tubular body 10 are comprised of a closure means, a hinge, a spring means, and a retention means.

The closure means may comprise two oppositely disposed arcuate elements 36 and 38 shown in open position in FIGS. 1 and 2 and in a closed position in FIGS. 3 and 4. The arcuate elements 36 and 38 are constructed so that when in an open position they are substantially flush with the core liner 22 and the inner diameter 40 of the cutting shoe 24 so as to present a substantially constant sectional area to a core sample as it is cut from the ocean bottom; the constant sectional area is best seen in FIG. 2. To achieve the substantially flush interior, the interior portion 18 may be counterbored. In addition, the arcuate elements are so designed that the elements 36 and 38 substantially close the interior 18 of the tubular body and form generally two equal halves of a hollow right circular cone, as shown in FIGS. 3 and 4.

Each of the arcuate elements 36 and 38 is rotatably attached to oppositely disposed hinges which may be comprised of a support ring 42, tabs 44 and 46, pins 48 and 50, and arms 52 and 54. The support ring 42 may be located within the interior 18 of the tubular body and positioned in a fixed location by any suitable means such as by being bolted through hole 62 to the tubular body 10. A lower end 64 of the support ring 42 is spaced from the cutting shoe 24 by a circular spacer ring 66 which rests upon a circular transverse face 68 of the cutting shoe 24. Tabs 44 and 46 may be attached to the support ring 42 by welding and are designed to be rotatably attached, in turn, to the arms 52 and 54, respectively, which may be accomplished by pins 48 and 50, respectively, inserted into corresponding holes in the tabs and arms. The arms, in turn, are rigidly connected to the arcuate elements 36 and 38, respectively, thus allowing the arcuate elements to be rotated from an open to a closed position. The support ring 42 may have oppositely disposed slots 70 and 72 designed to allow the arms 52 and 54 to be rotated.

Spring means such as torsion springs 74 and 76 are connected to the arcuate elements 36 and 38, respectively, and to the tubular body 10. In FIG. 1 the torsion springs 74 and 76 are shown in a biased position tending to move the arcuate elements together while in FIG. 3 the torsion springs 74 and 76 are shown in position after they have closed the arcuate elements. The arms have apertures at and 77 to receive the ends of the torsion springs so as to keep the springs in position. It is to be noted that the tabs 44 and 46, the arms 52 and 54 and the torsion springs 74 and 76 are located in the two longitudinal grooves 28 and 30, respectively, which is a factor in enabling the arcuate elements 36 and 38 to achieve their substantially flush position.

The retention means are connected to the'tubular body 10 and to the arcuate elements 36 and 38 and are for the purpose of holding the arcuate elements in an open posi-' tion during the descent and penetration of the core barrel into the ocean bottom and are responsive to downward sediment pressure for releasing the arcuate elements once removal of the device is started. The retention means may be comprised of catch elements 78 and 80 and holding elements 81 and 83. The catch elements 78 and 80 are each rigidly attached such as by welding to arcuate elements 36 and. 38,. resuept v lv an m y. be. .L-shap d s own in the figures. The holding elements, in turn, comprise hook portions 82 and 84 for engaging respectively the catch elements 78 and 80, and a trigger portion upon which the sediment forces act. f The trigger portion. of the holdingelements, in turn, comprise mounting elements-86 and 88 and planar slanted surfaces 90 and 92 whichare slanted so that they extend generally upwardly away from the tubular body 10. The generally V-shaped notch'formed-by each slanted surface and the exterior surface of thetubular body tends to wedge sediment against the surfaces and thereby cause activation when the device begins itsupward movement during removal. Each'of the holding elements comprised of the hook element, the mounting element, and the slanted surface may be made integral as is illustrated in our preferred embodiment. I e

Mounting blocks 94 and 96-may be oppositely disposed such as by welding or bolting upon the exterior surface 16 of the tubular body and contain pivot pins 98 and 100, respectively,-about which the holding elements are pivotally mounted by way of their mounting elements 86 and 88, respectively. The arrangement just described allows the hook portions 82 and 84 to project into the apertures 32 and 34, respectively, of the tubular body so as to engage the respective catch elements 78 and 80 which may also project into the respective apertures 32 and 34.

Operation The operation of our invention is relatively simple and quite reliable, two necessities that are required when apparatus is to function automatically in a hostile environment. The entire coring device is either lowered or dropped froma vessel and proceeds to descend to the ocean bottom. Usually because of its weight or by some driving mechanism the core barrel is driven into the bottom sediment to slice away a core sample.

The function-of the cutting shoe 24 is to do the slicing and direct a sample into the 'interior of the core barrel. In our invention the core sample will pass first into the interior of the cutting shoe then into the interior 18 of the tubular body 10 before entering the interior of the liner 22. As is noted in FIG. 2, a constant cross section presents itself tothe core sample so as to prevent any disturbance or damage to the sample.

During this penetration stage the exterior surface 16 of the tubular body 10 will experience a frictional drag of the sediment'as the device continues to penetrate. This friction will cause an upward force upon the pivotable holding element. Since the arcuate elements 36 and 38 were placed in an open position on board the vessel, there will be no tendency during penetration to cause closure as the hook portions and catch elements will remain engaged.

However, upon the removal of the coring device from the ocean sediment the surfaces 90 and 92 will experience sediment forces -opposin'g'their upward movement. These forces will be sufiicient to activate the device, the forces being created by the wedging of the sediment against the surfaces or by the pressure exerted against any fiat surfaced body as it moves through a fluid medium. The forces acting upon the surfaces and, therefore, upon the holding elements cause them to rotate about their respective pivot pins 98 and 100thereby pivoting the hook portions 82 and 84 from engagement with their respective catch elements 78 and 80. Removing the restraint from the biased torsion springs 74 and 76 allows them to force the arcuate elements 36 and 38 into a closed position as shown in FIGS; 3 and 4. V

I The advant'ages'in our invention are that the arcuate elements 36 and 38 close immediately upon lifting of the coring device. This will occur even before removal of the device from the sediment. Thus, the suction forces inherent in any pulloutfr'om the ocean bottom cannot act upon the core sample to remove it from the core barrel. In addition, the placement of a spring means within the system causes the arcuate elements to close immediately upon release thus supplying its own force of closing and not requiring the forces to come from outside the coring device as was done in the prior art. Furthermore, the holding elements may be so constructed as to operate very easily so that the slightest of forces acting upon the triggering portions pivot the holding elements out of engagement with the catch elements. This allows operation of our device in extremely soft sediment such as soft, oozy mud or clay and yet our device is still able to operate in the harder types of material without loss of efliciency. The broader applications available with our device makes it an extremely desirable tool since, in many cases, the type of sediment found at the ocean bottom is not known prior to receiving a sample.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

We claim:

1. A spring actuated core retainer comprising in combination:

a tubular body having a lower, an upper, an exterior,

and an interior portion; a hinge connected to said tubular body; a closure means rotatably attached to said hinge for opening and closing the interior of said tubular body;

spring means connected to the tubular body and to the closure means for biasing said closure means into a closed position; and

a retention means connected to the tubular body and the closure means for selectively holding the closure means in an open position and responsive to downward sediment pressure for releasing the closure means,

whereby said closure means is open during penetration of the ocean bottom and biased closed during pull-up from the ocean bottom. 2. A spring actuated core retainer as claimed in claim 1 wherein:

the spring means is a torsion spring. 3. A spring actuated core retainer as claimed in claim 1 wherein:

the closure means comprises two oppositely disposed arcuate elements which form when in a closed position two halves of a generally right circular cone;

each arcuate element being rotatably attached to oppositely disposed hinges;

said tubular body having transversely oppositely disposed apertures; and

said retention means comprising two catch elements each catch element rigidly attached to each of said arcuate elements, and holding elements each pivotally mounted upon the exterior portion of the tubular body, extending through the tubular body apertures for engaging the respective catch elements when the interior portion of the tubular body is open. 4. A spring actuated core retainer as claimed in claim 3 wherein:

the pivotable holding element comprises a hook portion for engaging the catch element and a trigger portion upon which sediment forces act to cause pivoting, the trigger portion disposed generally exterior of the tubular body. 5. A spring actuated core retainer as claimed in claim 4 wherein:

the trigger portion of the holding element comprises a mounting element and a planar slanted surface, said surface extending generally upwardly away from said tubular body. 6. A spring actuated core retainer as claimed in claim 5 including:

mounting blocks oppositely disposed upon the exterior of the tubular body; and said mounting element of said trigger portion pivotally attached, one mounting element to each of said mounting blocks. 7. A spring actuated core retainer as claimed in claim 6 including:

a support ring mounted to the interior portion of the tubular body for supporting the hinge; a core barrel connected to the upper portion of the tubular body for receiving a core sample; a cutting shoe connected to the lower portion of the tubular body for cutting a core sample; and a spacer ring located between the cutting shoe and the support ring for spacing the cutting shoe and the support ring.

References Cited UNITED STATES PATENTS Re. 18,500 6/1932 Stone -254 X 1,987,853 1/1935 Howard 175-251 2,022,100 11/1935 Wright 175-254 2,028,579 1/1936 Wright 175-254 2,215,710 9/1940 Miller 175-242 X 2,471,616 5/ 1949 Goodwin 175-254 3,285,354 11/1966 Sanders 175-242 NILE C. BYERS, 111., Primary Examiner.

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